1. Field of the Invention
The present invention concerns a silver halide color photographic photosensitive material having an improved granularity and color reproducibility, as well as a lower stain level after processing and stability of photographic property during storage simultaneously, and it particularly relates to a silver halide color photographic photosensitive material suitable for color reversal processing.
2. Description of the Related Art
In the color photosensitive materials, image quality and color reproducibility are important characteristics and various technical developments have been conducted for improving both of the characteristics.
In the image quality, the granularity is an important property and there is generally a trade-off relation that the granularity is more excellent but the sensitivity is lowered as the size of the photosensitive silver halide grain decreases. To this end, technique of improving the sensitivity/granularity ratio has been developed so far to obtain a higher sensitivity with an equivalent grain size or a smaller size with an equivalent sensitivity.
The technique for improving the sensitivity/granularity ratio of silver halide emulsion is generally classified into (1) increase in the light absorption amount per one grain and (2) improvement of the efficiency for utilizing absorbed light, that is, increase of the quantum sensitivity. For improving the sensitivity/granularity ratio of silver halide photosensitive materials, it is necessary to improve both of them. Since tabular silver halide grain has a shape of a larger surface area per volume and can increase an amount of spectral sensitizing dye that can be adsorbed per one grain as compared with a usual cubic or octahedral grain, it can also increase an amount of light absorption (refer, for example, to JP-A No. 59-133540). A technique of introducing dislocation has been known for improving the quantum sensitivity of the tabular grain. It is considered that since the crystal defect introduced into a grain represented by dislocation serves as a shallow electron trap for a photoelectron and prevents recombination between a photoelectron and a hole, the quantum sensitivity is improved. This technique enables to improve the quantum sensitivity of the tabular grain with large amount of light absorption and has contributed to the improvement of the sensitivity/granularity ratio in many products (refer, for example, to JP-A No. 63-220238).
On the other hand, the problem regarding the tabular grain into which dislocations are introduced is that the introduction of the dislocations hinders the improvement of the aspect ratio. Usually, dislocations are introduced into the grain by an interlayer lattice gap by forming layers having different halogen compositions in the course of crystal growth. Therefore, since steps or kinks are formed on a principal surface which was substantially smooth in terms of atoms after introducing the dislocation, the crystals are grown not only in the direction of the crystal edge but also in the direction of the crystal thickness, so that it is considered that anisotropic growing property of parallel twin tabular grain is deteriorated. Because of the reasons described above, it is difficult to increase the aspect ratio of the tabular grain into which with dislocation is introduced, resulting in hindrance of further improvement of the light absorption.
As a means for improving the quantum sensitivity without hindering the increase in the aspect ratio, a shallow internal latent image technique of covering thinly latent image forming sites with a silver halide layer (for example, refer to JP-A No. 63-158546) or a grain in which a silver halide protrusion portion is formed on a host grain having a high aspect ratio (for example, refer to JP-A Nos. 2003-15245 and 8-69069) has been known.
However, with respect to the technique described above, or the silver halide grains, particularly, silver halide emulsion containing the latter silver halide grain, although the granularity is improved, it involves a significant problem that IIE imparted from the layer to other layer is not sufficient as compared with the case of using the conventional dislocation type silver halide grain and that stains increase after the processing due to the amount of the sensitizing dye (hereinafter referred to as residual color in the invention).
With respect to the color reproducibility, various attempts have been made for improving the color reproducibility such as control of the spectral sensitivity, utilization of correction on a side absorption of a colorant by masking or utilization of an inter-image effect (IIE). Control of the IIE is particularly important as a control means to provide a desirable color reproducibility. The IIE in the color reversal photosensitive material is caused when iodide ions released from a photosensitive silver halide grains in the first development are diffused and adsorbed to silver halide grains in other layers to retard the development thereof. That is, it is desirable to increase the iodide content in the silver halide emulsion of a layer that exerts the IIE and to make the iodide content as small as possible in the layer intended to undergo the IIE. In view of this fundamental characteristic, it is difficult to control the applicability and the acceptability of the IIE independently, and therefore, difficulties arise, for example, in the case where it is intended to exerts the IIE but, at the same time, intended to be susceptible to the IIE. As measures for solving the difficulties, it has been devised to dispose a special layer for providing the IIE (IIE providing layer) (refer, for example, to JP-A No. 2002-351029). When the special layer for providing the IIE is provided, it is necessary to increase an amount of a color impurity preventing agent to be used since the color impurity occurs in the adjacent emulsion layer. Accordingly, the residue of the sensitizing dyes after the processing increases, resulting in an increase in the residual color. Further, while it has been known that the color impurity preventing agent shows the stain preventive effect as the effect of an image storability (for example, refer to JP-A No. 2003-43647 (p. 57)), the effect on the residual color due to the sensitizing dye has not yet been known.